When evaluating an onshore contract electronics manufacturer, one of the things you will consider is whether it has the equipment and the experience to handle the smallest surface mount components you will use on your printed circuit boards.
One of the first questions to ask in this situation: Do you need a contract manufacturer that can handle today's smallest components? These are exceedingly small; state-of-the-art 01005 components measure only 0.01 x 0.005 inches, and 0201s are about 0.02 x 0.01 inches. To put this in perspective, 0.005 inches is about the thickness of a sheet of copy paper.
Obviously, parts this small can't be placed on printed circuit boards by hand. Manufacturers use pick-and-place machines to put them on boards at speeds of up to 60,000 parts per hour. A lot of US contract manufacturers don't find it worthwhile to invest in SMT lines that can handle the smallest components. Z-Axis does have this capability, but we're rarely asked to use it.
Why? The components are just too small! The 01005s and 0201s are great in products such as hearing aids and smartphones, where users demand the smallest product possible, and every hundredth of an inch of board space matters. Most of these products are produced in very high volumes (millions of boards a month) at offshore facilities.
We manufacture a lot of electronic products here, but the boards we make usually go into medical instruments, commercial products like LED lighting, or industrial products like motion control systems for factories. Production volumes range from tens to thousands of boards per month. Compact size is often important for these products, but it's not usually the absolute driving factor. Other considerations -- such as the ease of laying out and routing traces on the board and the ability to make and test prototypes by hand -- are more important than saving a few tenths of an inch of board space.
Tiny components such as the 0201 are usually just not worth the trouble for most designers. If you don't plan to use 0201 or 01005 components in your design, does it matter if your contract manufacturer can handle them? The answer depends on two related packaging trends:
- Micro ball grid arrays (MBGAs): They typically have six to eight connections (balls) located on the bottom of the package, with a ball-to-ball spacing (pitch) of 0.4mm (0.02 inches) or less.
- Micro lead frame (MLF) or "leadless" packages: They have connections arranged along the edge of the package, similar to a traditional SOIC package, but the connection is flush with the package, rather than extending horizontally at the base. A 3 x 3mm package with 12 connections may have a pad size of 0.25mm (0.01 inches) and a pitch of 0.5mm (0.02 inches).
In our business, we have seen the use of MBGA and MLF packages grow tenfold over the last five years. Although MBGA and MLF packages are larger than 0201s, they're still small enough to blow away with a sneeze. Significantly, the lead size and pitch is about the same as a 0201. These tiny feature sizes require more sophisticated manufacturing processes to place and solder the components reliably with good product yields.
If your designs use MBGAs or MLFs, look for a manufacturer with experience placing 0201 components. The ability to work with the tiniest packages is a good indicator that the manufacturer can handle the fine pitches of your MBGA and MLF packages.